Keep an eye out for these symptoms if horsepower is the one thing you live for.
It's a sad (or comforting depending on your philosophy on life) thing that entropy is a universal law. No matter how hard we try, the natural tendency for things to wear out and break down as time moves on will eventually claim everything we know. That includes lives of loved people and pets, homes that house families and childhood memories, and even your own body will weaken and deteriorate until one day it gives up the fight. We don't exactly know why the universe works this way, cruel thing that it is.
What we do know, however, is how the symptoms of entropy begin to wear away at different things. In this case, Jason Fenske of Engineering Explained uses his engineering background to explain the processes that ultimately claim the lives of an engine.
That usually happens once a host of problems have already bogged down the engine, but before these ultimately claim a motor's life, they first rob it of precious horsepower. To break down these power-sucking symptoms of entropy like a true scientist, Fenske reverse-engineers the process by focusing on the four things an engine needs to function properly. That would be fuel, air, spark, and compression. Over time, air has a harder time making its way to the combustion chamber, the chamber itself looses the ability to retain compressed air and gas, spark plugs get unburnt fuel and oil on them, and fuel injectors or intake valves can have their flows impended upon. When these fail together, kiss that engine goodbye.